Muscular Dystrophy

Neuromuscul Disord. 2004 Jan;14(1):39-45.

Changes in motor cortex excitability in fascioscapuloheral muscular dystrophy.

Di Lazzaro V, Oliviero A, Tonali PA, Felicetti L, De Marco MB, Saturno E, Pilato F, Pescatori M, Dileone M, Pasqualetti P, Ricci E.

Institute of Neurology, Universita Cattolica, Largo A. Gemelli 8, Rome 00168, Italy.

Previous studies found that some patients with severe, early onset facioscapulohumeral muscular dystrophy (FSHD) present epilepsy and mental retardation. This suggests a functional involvement of central nervous system in severe FSHD. It is unknown whether minor functional changes of central nervous system are also present in less severe forms of FSHD. To investigate this, we examined the excitability of neuronal networks of the motor cortex with a range of transcranial magnetic stimulation paradigms in 20 FSHD patients with heterogeneous clinical severity and compared the data with that from 20 age-matched healthy individuals and from 6 age-matched patients with other muscle diseases. There was significantly less intracortical inhibition in FSHD patients (mean responses +/- SD reduced to 58.1+/-43.5% of the test size) than in controls (mean responses +/- SD reduced to 29.3+/-13.5% of the test size; P=0.025) and in patients with other muscle diseases (mean responses +/-SD, reduced to 30.6+/-11.7% of the test size; P=0.046). No significant difference was found between the control group and patients with other muscle diseases (P=0.970).

Muscle Nerve. 1998 May;21(5):662-4. Related Articles, Links

Functional involvement of cerebral cortex in Duchenne muscular dystrophy.

Di Lazzaro V, Restuccia D, Servidei S, Nardone R, Oliviero A, Profice P, Mangiola F, Tonali P, Rothwell JC.

Istituto di Neurologia, Universita Cattolica, Rome, Italy.

Transcranial stimulation was performed in 4 patients with Duchenne muscular dystrophy and 4 control subjects. The patients’ central motor conduction time was normal. The threshold for evoking electromyographic responses using electrical anodal stimulation was the same in both groups, but the threshold for stimulation with a circular magnetic coil at the vertex was higher in the patients. This is compatible with reduced cortical excitability that may be related to the deficiency of brain synaptic dystrophin.

Electroencephalogr Clin Neurophysiol. 1997 Aug;105(4):297-301.

Magnetic stimulation study in patients with myotonic dystrophy.

Oliveri M, Brighina F, La Bua V, Aloisio A, Buffa D, Fierro B.

Institute of Neuropsychiatry, University of Palermo, Italy.

To further define motor nervous system alterations in myotonic dystrophy (MD), motor potentials to transcranial and cervical magnetic stimulation (MEPs) were recorded from the right abductor pollicis brevis muscle in 10 patients with MD and in 10 healthy controls. Cortical and cervical latencies, central motor conduction time (CMCT), stimulus threshold intensity and cortical MEP amplitudes expressed both as absolute values and as %M were analysed. MEP cervical latency, absolute or relative amplitude and excitability threshold did not significantly differ in patients and controls. The mean cortical motor latency and CMCT were significantly prolonged in MD patients with respect to normal subjects. Moreover, CMCTs were found to be significantly related to stimulus threshold intensity (P = 0.03) and only marginally related to absolute cortical amplitude (P = 0.06). These findings are indicative of a central motor delay, also related to decreased excitability of motor neurons, in patients with MD. No correlations were found between individual neurophysiological parameters and age, duration of disease and clinical impairment. Our results suggest that magnetic stimulation studies can detect subclinical dysfunctions of the central motor system in MD patients, as one of the multisystemic manifestations of the disease, rather independent of the primitive muscle damage.